1. Field of Invention
The present invention relates to a safety shield for a needle and more particularly to a shield assembly which attaches to the hub of the needle, and allows use of the needle on a syringe, needle holder or other fluid handling device.
2. Description of Related Information
In the medical arts, sharp pointed needles are used for a variety of procedures. Devices having sharp pointed needles are used for administering fluids to patients either directly or into intravenous apparatus, and in various blood drawing applications either with syringes or with specialized holders for filling evacuated tubes.
Exposure to blood borne pathogens is a recognized hazard by anyone associated with the medical arts. As a result of this recognition, numerous protocols for use of needles have been developed and are practiced. The problem of transmission of blood borne pathogens not only exists for the physician, nurse or phlebotomist using the needles, but also for support workers all through the hospital. Since most needles in use today are single-use and disposable, hospital service personnel are at risk from needles that are not properly handled by the users.
The use protocols generally dictate in detail when and how a needle will be used and how it should be disposed of. The problem with many protocols for handling needles is that the protocols often require users to perform additional steps in a procedure. With the press of time and simple carelessness certain practices regarding handling of used needles are sometimes disregarded and injuries still occur. The medical device industry has responded to the problem by producing a wide variety of sharps collectors, needle shielding devices and the like to assist practitioners in their need to reduce the occurrence of needle injuries.
Many devices have been developed for shielding needles after use to avoid exposing other workers to used needles. A representative listing of many of these devices is found in U.S. Pat. No. 4,982,842 to Hollister et al. Hollister et al. lists 90 U.S. patents of various devices for guarding a needle as part of the background for the present shielded needle container. Hollister et al. discloses a stand alone adapter that has a male and female end for mating with a needle assembly and the ejection end of a syringe. The device of Hollister et al. includes a housing mounted to the adapter which may be pivoted to a position in alignment with the needle for enveloping the needle and locking the needle to retain it in the housing. The Hollister et al. device increases the unusable or "dead" volume of the device on which the adapter is mounted, requires an additional part which increases the projection of the needle hub, and the mechanism for holding the cap onto the needle snaps onto the needle itself, which may create an aerosol of any fluid remaining on the needle. Also, if bevel position is important to the intended use of the needle, the Hollister et al. invention must be carefully aligned with the needle point when mounted.
U.S. Pat. No. 5,207,653 to Janjua et al. discloses a needle cap with a longitudinal slit having a width greater than the width of a needle. According to Janjua et al., the needle cap is adapted to be pivotally connected with the needle and hub piece. Janjua et al. also discloses that the needle cap is usable with a syringe or with a needle holder for fluid collection tubes. The device disclosed by Janjua et al. mounts on the needle hub with a pivot, but since it only pivots in one plane, unless the needle point is precisely with the hub oriented during assembly, the shield may interfere in some applications.
Many of the devices listed in the background of the Hollister et al. patent, the Hollister et al. invention itself and the Janjua et al. invention all attempt to address the recognized need to protect medical and service personnel from needle sticks. There are several recurrent problems in varying degrees with all these devices. Many of the devices are somewhat complex, hence are significantly more costly than an unprotected device. Many of the devices increase the complexity or increase the difficulty of performing a procedure. Some devices are so specific that they preclude use of the device in certain procedures. For these and similar reasons most of the devices in the Hollister et al. background have never been successfully commercialized.
Blood drawing is one application that is particularly sensitive to needle point orientation. Most phlebotomists carefully align a needle point with the beveled face away from the skin so that the needle point placement may be precisely controlled. A needle assembly as disclosed in Janjua et al. would either sometimes be clumsy to use because the shield would sometimes be in the way or, alternatively, more expensive because of the need to carefully orient the point during manufacture. Additionally, in Janjua et al., while there is a recognition of the need to secure the cap in the closed position over the needle, all of the solutions proposed require additional steps such as securing the cap with an adhesive or twisting the cap.
Although there already are many shielded needle devices, there is still a need for a shielded needle device that is easily manufactured, applicable to many devices and simple to use. Additionally, the needle device should not interfere with normal practices of use. Such a device is described below.